Kept secret for weeks, the vision of what will replace the collapsed Interstate 35W bridge became public Monday: a design that emphasizes simplicity and safety.

With a $234 million contract formally in hand, the team led by Flatiron Constructors unveiled its renderings at the State Capitol, promising a bridge that would last 100 years and enhance the Minneapolis riverfront.

The design's release came hours after the state dismissed complaints by two losing bidders that the selection process was flawed and led to the costliest proposal being chosen.

The concrete box-girder bridge features twin 504-foot central spans over the Mississippi River. It will have special LED lighting, railings that allow drivers to see the river and a sensor system to detect potential failure.

"Gateway monuments" would decorate the bridge at each end. Observation decks are planned for the river's edge at the base of the hourglass-shaped 70-foot piers.

"It is a modern concrete bridge for the future, a bridge of its time," said Linda Figg, whose company, Figg Engineering of Florida, is the designer with the Flatiron team.

Flatiron, based in Colorado, had the most expensive bid of the four competing teams but won the contract on the basis of the quality of design and other factors. The company hopes to start construction by Nov. 1, three months after the 40-year-old bridge collapsed, killing 13 people and injuring more than 100. It vows to finish by Christmas Eve 2008.

The company will be seeking the public's opinion on the design of the piers and monuments, along with whether the bridge's color will be white or sandstone.

The bridge is also designed to allow for a pedestrian bridge to be suspended from the underside of the deck. It would connect parkland areas on either bank.

Two of Flatiron's Florida-based partners on the I-35W project, Figg and Johnson Bros. Construction, have worked on projects in the Twin Cities. Figg helped build the Wabasha Street bridge in St. Paul; Johnson worked on the Hennepin Avenue suspension bridge.

Flatiron and Figg emphasized Monday that they would be hiring the equivalent of 400 full-time employees, nearly all of them local. "Minnesota workers will build the bridge," said Peter Sanderson of Flatiron.

The design brought a generally favorable reaction from Ted Tucker, a Minneapolis Planning Commission member and a resident of the Marcy-Holmes neighborhood near the bridge. Tucker said the design's features accented the river crossing and appeared to give motorists a better view of the river.

"That was one of our big complaints about the old bridge ... you never really knew when you were crossing this major river, and they seem to be interested in marking it," he said. "It's one of the great views of Minneapolis."

Protest effort is rejected

The bridge design was released after the state rejected a protest effort by C.S. McCrossan of Maple Grove and a team of Ames Construction of Burnsville and Lunda Construction of Black River Falls, Wis.

In their protest letter, the two losing teams noted that they had built dozens of bridges in Minnesota and argued that they had been "misdirected" about what MnDOT wanted. The agency, the protesters said, had put great emphasis on speed and cost, then awarded the contract to the team with the most expensive proposal and the longest timeline.

But the state Department of Administration said that MnDOT followed the "highly prescriptive statutory requirements" of such design-build projects and that nothing about it was "arbitrary" or "capricious."

Dean Thomson, the lawyer representing Ames/Lunda and McCrossan, said Monday evening that his clients were disappointed in the decision -- and in the fact that they were not allowed to evaluate each team's technical scores before the contract was signed. "We have now prevented the public from determining whether this really is the best value," he said.

He said he and his clients "will be taking a hard look" at the scoring data before deciding what to do next.

Details of other bids and scoring

In outlining the decision to hire Flatiron, MnDOT released a series of documents that listed the shortcomings of the unsuccessful bidders.

In addition, other documents provided details concerning the decisions of a six-person technical committee, whose scoring led to Flatiron's selection.

The scoring documents showed that none of the committee members gave the Flatiron team a technical score lower than 87 (it had an overall score of 91.47). In contrast, none of the panel members gave any of the unsuccessful bidders a score higher than 77.05.

Under the heading "experience and authority of key individuals," a category where a company could be given a maximum of 20 points, the documents released Monday showed that Flatiron had a technical score of 18.83, compared with 11.43 for Ames/Lunda, 12.07 for McCrossan and 14.33 for Walsh/American Bridge.

In reviewing the Ames/Lunda proposal, the technical committee found that while the lead bridge designer had 27 years of experience, the project manager did not have that experience on a major river crossing project or on a design-build project.

The panel also found that the team's design left a bridge pier "susceptible to movement due to thermal effects" and that "the future profile of 35W was not compatible with the future construction of interchanges at University Av. and 4th Street SE. as it required the removal of the bridges at 2nd St. SE. and reconstruction of the river bridge."

The panel also noted that, in the Ames/Lunda proposal, "the visual quality experience for the drivers of 35W appeared lacking."

In addition, the panel said, the Ames/Lunda "public relations staff appeared too small for this size and type of project."

MnDOT representatives confirmed that Santiago Calatrava, the renowned Spanish architect, did try to offer a bridge design as part of the proposal submitted by the Walsh/American Bridge team. MnDOT's Kevin Western, a member of the six-person evaluation team, said the design was rejected because of a lack of redundant structural features.

Jon Chiglo, MnDOT's manager for the project, said Monday that the cost of making this particular design ready for light rail was $4.7 million. Early estimates were in the $20 million to $30 million range.